A question for the BD turbo swap owners

[Kraziken]

I know this might be a tough question to answer, since there is a small crowd (although growing in numbers. :grin: )

What is the biggest TMIC I can fit? I don't think there is much room under the hood for a larger TMIC.

I'm considering running my GT30R with the stock STI top mount intercooler. One, because I can get to use my new turbo sooner, and two, I might have less turbo lag (at the expense of max power).

Anyone running a Front Mount? What model did you go with? I looked at Perrin, but it looks massive and I'm not sure it will fit. The other candidate I've been investigating is the APS 525.

[Huffer]

Might be easier if you measure the space you have, and see what TMIC's are available based on the volume you have to work with.

[grayguy]

Depends how much your willing to cut. With a little work I fit a 28"x12"x2.5 FMIC in my 98'

https://sl-i.net/FORUM/images/imported/2007/06/FMIC3-1.jpg

https://sl-i.net/FORUM/images/imported/2007/06/FMIC-1.jpg

https://sl-i.net/FORUM/images/imported/2007/06/FMIC5-1.jpg

[Garrison]

If you dent your firewall, you can setup one of the massive eBay tmic's. Otherwise, 02-05 wrx intercoolers will fit, but you will need to maneuver things around. 06+ are the slimmest (best fitting) tmic

[Garrison]

I did some more research for you, apparently in terms of flow, the Sti unit falls just slightly behind the eBay TMIC with a 2psi drop after the intercooler. The eBay TMIC has .2psi drop after the intercooler.

However, the Sti tmic cools significantly (about 75 degrees) better than the eBay version per a given boost. The wrx intercooler, just slightly less so, but still significantly better cooling. Overall, unless you're ready to drop some dough for a top of the line intercooler, just stick with what you have.

[Kraziken]

Thanks,

I wonder what brand you have, and did you retain the fog lights?

I still have some hurdles as I have a splitter, but need some custom work for it to fit if I stick with TMIC.

[grayguy]

I used a $300 Godspeed intercooler, and no, I lost the fogs. I ended up cutting the whole back of them out and just leaving the front face and mounting brackets.

[Reuben]

Dude, factory TMIC's are good for 300WHP, Easy. No need to run anything other than the STi TMIC, they are fine for the job. And nothing looks better than factory STi parts, really :D

https://sl-i.net/FORUM/images/imported/2011/08/IMG_6367-1.jpg

[Garrison]

While on the topic of turbo piping, on a 50/50 bpv the bpv routes back into the intake piping, pre turbo, right?

[Reuben]

Pre turbo, Post AFM, yup.

My recommendation is to go 100% recirc with a factory BOV. Once you get used to the car, you can hear the factory ones just fine.

[Garrison]

Thank you kindly sir, I found a forester XT intercooler so I've got some room to play around in there. And oem is exactly what I'm doing

[anothernord]

STi TMIC is the best option for it's price point, in my opinion. It doesn't have the cheesy aftermarket look, it blows away eBay intercoolers, and outperforms WRX intercoolers.

[chuckthefuk]

There are trade offs to both setups

TMIC
- Heat soak
- Awkward piping bends to fit a GT30R
- Less lag

FMIC
- Less heat soak
- Depending on how your ROTATE your GT30R you can reduce the amount of pipes depending path of hot/cold pipes
- More lag

With a larger turbo (GT30) on 2.0 ltr block the lag is not that noticable. Sure if your using a smaller turbo it will spool quickly but with longer pipes to pressurize it does cause more lag before you hit boost.

FMIC can clean up , free up and reduce heat altogether however it involves more work in general to fit.

-Chuck

[Reuben]

I'll just put this out there. I've never had heat soak issues with my TMIC, after a hot and fast boost, numerous times i've stopped, put my hand over the TMIC and it felt bloody cool to the touch. Heat soak is only and issue when going slow, like between lights and in traffic, in which case, you don't really want to be hitting full boost... Keep that for the open road...

That's how I've rationalised keeping my TMIC I guess, lol. That and I don't want the headache of all that extra piping and hacking up my beautiful car :P (God, i've had enough issues recently trying to track down a bloody boost leak with the limited piping you do get on a TMIC!!! (I'm suspecting my y-pipe gaskets have popped))

THAT SAID. I have seen numerous articles on intercoolers, and TMIC's really do become a limiting factor beyond 300-350, whp, after that point you can usually make some large gains by the added cooling from an FMIC. BUT, here's the trick... Below 300hp, it makes fuck all difference. Below 300HP FMIC's really are a ricer mod, all show no go. Generally speaking of course...

[chuckthefuk]

Have you ever touched the underside of the intercooler next to the Throttle Body & Turbo?

Pure heatsoak. You cant judge the topside since its constantly being battered by air.

-Chuck

[Garrison]

THAT SAID. I have seen numerous articles on intercoolers, and TMIC's really do become a limiting factor beyond 300-350, whp, after that point you can usually make some large gains by the added cooling from an FMIC. BUT, here's the trick... Below 300hp, it makes fuck all difference. Below 300HP FMIC's really are a ricer mod, all show no go. Generally speaking of course...
I would never say that an intercooler that produces greater temperature reduction within the combustion chamber was a ricer mod; it just so happens to share the aesthetic aspect.

[grayguy]

I know my little td04 heated my big dual core 3.5" thick TMIC up like crazy, didn't even take spirited driving

[Reuben]

THAT SAID. I have seen numerous articles on intercoolers, and TMIC's really do become a limiting factor beyond 300-350, whp, after that point you can usually make some large gains by the added cooling from an FMIC. BUT, here's the trick... Below 300hp, it makes fuck all difference. Below 300HP FMIC's really are a ricer mod, all show no go. Generally speaking of course...
I would never say that an intercooler that produces greater temperature reduction within the combustion chamber was a ricer mod; it just so happens to share the aesthetic aspect.

Well I guess you don't see what I see I suppose. The majority of FMIC's here in NZ are paired with no more than a pod filter and atmo blow off valve. None of these mods aid performance on a stock WRX, with stock management and everything else, let me tell you that now. FMIC's are strongly related to ricers in NZ, my bad for not pointing that out earlier.

Then you take the fact that subaru could so easy design their cars to run on an FMIC... heck, they relocated the turbo to the front of the engine on the gen 5's no sweat, but still they use a TMIC, so in stock form, there really is nothing wrong with the TMIC.

All I'm saying is, the FMIC should not be the first mod - as it is so often done here in NZ. It's one of those mods best left down the line, you at least want a tunable ECU before you consider bothering with a front mount.

[Garrison]

Now that I completely agree with. Fmic when you can tune, and make use of the added temperature reduction.

[HeresMyMind]

I have a perrin TMIC going in. and its huge. no clearance issues. just a pain in the butt to get in there at first. the stock v.7 or v.8 sti top mount is good for 350whp EASY. I am trying to trade my perrin for one. here is a picture of my stock wrx one. The ebay godspeed ones rub a but on the firewall area.

-B

https://sl-i.net/FORUM/images/imported/2011/08/3uek8-1.jpg

[Garrison]

Did you flip your throttlebody? I see the throttle cables on the left side of the Tb.

[HeresMyMind]

stock wrx throttlebody

-B

[Garrison]

Gotcha. What have you TMIC guys to the TMIC to combat heat soak? Does aluminum tape on the bottom (on the end tanks, not the actual fins) of the intercooler help at all?
Also, have you all custom fabricated hood-scoop -> TMIC splitters for the stock (1998) legacy hoodscoop? Does the stock hood-scoop even actually flow enough air?

[HeresMyMind]

heat soak with a stock td04 isnt really noticable except when I autocross on hot days. Thermal tape does help. Wrapping your downpipe and uppipe are the best things you can do to combat it.

as for a splitter. I am currently fabricating one. like this one:
https://sl-i.net/FORUM/images/imported/2011/08/DSC07188-1.jpg

and I will put rubber surrounds on the top to seat snug with the stock hoodscoop.

keep in mind I have a perrin tmic to fab one for so its HUGE lol
-B

[Reuben]

Oh that's right, I keep forgetting a lot of you guys don't have splitters. I suppose that makes a difference, especially since not only is it ducting air to the IC, but it's also blowing air down onto the turbo, and away from soiling up the engine bay (This is when using the stock BG splitter and IC).

[Kraziken]

Yeah, this question was in relation to a GT30R. So with a TMIC, I'd be ultimately leaving power on the table I think in favor of keeping a stock location intercooler.

I also have the 8mm phenolic spacers installed, which now I think I regret. It makes the hood clearance even more of a problem. Even with the stock STI TMIC, it barely clears now. So the question is whether I pay a big price in custom fabrication to modify the hood to allow for something like a Spearco TMIC, which ultimately might have heatsoak problems, or going FMIC and risk losing the fogs, and pay for custom piping.

I think I'm leaning toward the FMIC now. Looking for something 380+ whp. I can't justify paying the custom fabrication and leaving power. I still have to research what FMIC to use.

The next question on the table is whether to go rotated intake manifold, to gain smaller tubing and better response at the expense of air-conditioning. Ugh, decision, decisions.

[Garrison]

The next question on the table is whether to go rotated intake manifold, to gain smaller tubing and better response at the expense of air-conditioning. Ugh, decision, decisions.

You live in Seattle? Man, you don't need no dang a/c.

[Kraziken]

The next question on the table is whether to go rotated intake manifold, to gain smaller tubing and better response at the expense of air-conditioning. Ugh, decision, decisions.

You live in Seattle? Man, you don't need no dang a/c.

Heh, I know, and I tend to have a higher tolerance of heat in the first place. I may have used it once this year. Still the more unrefined the car gets, the less the wifey likes it. :lol:

[Reuben]

I use AC all the time, not for temps (when it's hot outside I roll the windows down and revel in it), but for condensation during winter mostly.

Anyway, for those numbers, yeah, FMIC would be a good choice. Just don't buy a pre-made piping set, do it totally custom so you don't have to remove your fogs. And you don't have to get a massive IC either, look at the size of a TMIC, and that only has a tiny scoop feeding it. Basically make it only as big as you need.

[lord flashheart]

alot of people here talking about "i got this intercooler bla bla bla.."
remember the manifolds play a part in your fitment. the STi/WRX throttle body is also shorter so it sits farther forward.
if you have say a legacy turbo manifold you will be hard pressed to fit a 02 wrx in it. i know this cuz my manifold is a EJ25D and i can barely fit the FXT I/C

[lord flashheart]

oh and PS i would take the top mount anyday.
especially with the GT35R. that turbo spools kinda late so u need to reduce eveybit of lag you can.
someone on nasioc i believe did some dyno work with top mounts and front mounts and the front mount gave a couple HP in the higher RPMs but it was like very small like 7hp if i remember right. but they saw that the front mount was causing more turbo lag.
personally i would take 200hp starting at 2500 than 300hp at 4500. just my 0.02

[Garrison]

i know this cuz my manifold is a EJ25D and i can barely fit the FXT I/C
Same here.

[Garrison]

Made a splitter yesterday out of .025" aluminum. Which worked decent, but I might go just slightly thicker, for more rigidity, if I were to do it again.

[Kraziken]

I really would like to stay with the top mount. As it is with the phenolic spacers, I had to grind some of the hood support because it was rubbing on the coolant overflow tank cap.

The EDFC motors for my Tein setup have made tiny indentations on the hood. Another problem I have to fix. I might have to ditch the EDFC. Us Legacy folks just don't have as much clearance.

Thought was to make some custom louvers or bulges on the side to allow for the EDFC. Or a complete body rework of the hood to allow for the EDFC and the taller TMIC. I don't know. The car would look strange with a huge power bulge down the middle I think?

[chuckthefuk]

Hood spacers work.. Washers and longer hardware.. add the cool drifto vented hood to any US legacy :-D
-Chuck

[lord flashheart]

Dude, factory TMIC's are good for 300WHP, Easy. No need to run anything other than the STi TMIC, they are fine for the job. And nothing looks better than factory STi parts, really :D

https://sl-i.net/FORUM/images/imported/2011/08/IMG_6367-1.jpg


Dude, factory TMIC are limited by how much air you can get to them our hood scooped are so small you can't get enough air thru the intercooler and above 60mph the air goes right over the scoop. Fmics are the way to go (remember our cars were designed in Japan where he average speed is like 32mph or some shit). I got my fmic in the mail a couple days ago. TMIC ftl. I saw it really bad with my car. In my car at 80mph my air temps were in the 180+ range, in traffic I was in the 200+ range switched to a rs scoop and it came down to like 130. I'm at 162whp so I kinda doubt that the oem scoop and intercooler are good for 300whp (380chp). This is also based on what I've seen on the dyno. 350chp with a big STi scoop/intercooler is about the limit if you ask me..

[lord flashheart]

I know what I said in the earlier post which is partially true but I have learned a lot and we also have our own dyno, so now I know that I was dumb b4 and have learned a lot about the science of intake and exhaust systems

[chuckthefuk]

Heat Soak! End of story.

Flashheart has very good points but its not a practicle real world application. Driving in traffic with a car tuned for *** amount with a top mount will negate the affects of the tune..

Highway runs sure either application is good but it all depends on how you use your car.

Just my 2 cents.
- Chuck

[anothernord]

One of my friends put down 411 TQ and 380 WHP on a AMR top mount and on 06/07 Scoop. That was one E85, though.

My opinion is that with a proper splitter, and water spray system, a TMIC can be just as effective as a FMIC. How often does one do a WOT pull with 300+ WHP in traffic? If for some reason you must, hit the I/C Sprayer on, and you're good.

[lord flashheart]

I still disagree with that.
i find that you can make a TMIC more effective, and all that, but its still less effective than a front mount. ive seen FMICs do 600HP+, and mitchs 807WHP EJ25 used a fmic. and my close friend had a LGT and is getting turned down by tuners saying "i wont tune your car any higher till you get a front mount intercooler' and he is at 312WHP with a perrin tmic.

you can make a TMIC more effective, but in general the FMIC will be more effective. especially becasue the air flow is more direct air flow plus you have fans behind it, and you can run a bigger intercooler in the front than on the top. air over air intercoolers are only as good as the amount of air you can get thru it.. a hole in your hood with a air scoop versus an air dam with direct air flow.. no contest.

[mike-tracy]

Despite FMIC having certain advantages, LordFlashheart, some of us want to stay TMIC for a variety of reasons. And want the best option that fits.

[lord flashheart]

oh i know, and in many cases, TMIC is better for the application. but as a general rule of thumb, the FMIC is more efficent at cooling.